Follow-up of #489

[sjaeckel]

This is a follow-up of #489

It adds "automation" of the modifications to tommath.def and a travis job to check for this.

Additionally the proposed split-up of mp_rand.c is done and the modifications to s_mp_rand_platform.c are reverted.

[madebr]

FYI, this are the results of building libtommath on linux gcc, linux clang, macos and windows msvc: conan-io/conan-center-index#2904 (comment)
Don't mind the .la errors, I forgot to remove these.

[czurnieden]

I can't tell a lot about the Windows related changes, but the rest I like!

[madebr]

With the following changes, this pr allows building the tests linked to the dll.

--- a/appveyor.yml
+++ b/appveyor.yml
@@ -19,3 +19,4 @@ build_script:
         nmake -f makefile.msvc all
 test_script:
 - cmd: test.exe
+- cmd: test_dll.exe
--- a/makefile.msvc
+++ b/makefile.msvc
@@ -71,10 +71,15 @@ $(LIBMAIN_D) $(LIBMAIN_I): $(OBJECTS) tommath.def

 #Build test suite
 test.exe: $(LIBMAIN_S) demo/shared.obj demo/test.obj
-       cl $(LTM_CFLAGS) $(TOBJECTS) $(LIBMAIN_S) $(LTM_LDFLAGS) demo/shared.c demo/test.c /Fe$@
+       link $(TOBJECTS) $(LTM_LDFLAGS) $? /out:$@
        @echo NOTICE: start the tests by launching test.exe

-all: $(LIBMAIN_S) test.exe $(LIBMAIN_D)
+#Build test suite for dll
+test_dll.exe: $(LIBMAIN_I) demo/shared.obj demo/test.obj
+       link $(TOBJECTS) $(LTM_LDFLAGS) $? /out:$@
+       @echo NOTICE: start the tests by launching test_dll.exe
+
+all: $(LIBMAIN_S) test.exe $(LIBMAIN_D) test_dll.exe

 tune: $(LIBMAIN_S)
        $(MAKE) -C etc tune

[madebr]

The test is failing in test_mp_fread_fwrite.
It looks like we need to override the default runtime when building dll's.
By default static runtime is used, but that does not work because the mp_f* api calls pass FILE* handles.
So use the shared MD runtime by default instead.
People can override the default by setting it in CFLAGS.

--- a/makefile.msvc
+++ b/makefile.msvc
@@ -11,7 +11,7 @@

 #The following can be overridden from command line e.g. make -f makefile.msvc CC=gcc ARFLAGS=rcs
 PREFIX    = c:\devel
-CFLAGS    = /Ox
+CFLAGS    = /Ox /MD
 LDFLAGS   =

 #Compilation flags

[czurnieden]

Ubuntu's Bionic Beaver is version 18.04, you might change the comment above the distribution settings in .travis.yml otherwise: looks good for me!